Sams Teach Yourself Microsoft SharePoint 2003 in 10 Minutes

A picture library is very similar to a document library in that it's also a Web Part designed to store documents and allow users to attach metadata to the documents. The picture library is designed with the assumption that users will want to store graphics files in the library. Thus, the Marketing department might create one picture library on its home page for approved logo files and another one for graphics and photographs for use in publications. Or, the Human Resources department might create a picture library for company events and then create subfolders for different events, such as the Christmas party and company picnic.